In many textile yarn processing machines, such as two-for-one twisters and the like, spindle assembly stations for the processing of yarn are positioned along each side of the machine. These spindle assembly stations each include a rotatably driven rotor mechanism having a horizontally-extending reserve yarn storage disc and a generally vertically-extending hollow axle defining therewithin a yarn passageway extending therethrough and radially out of the reserve yarn storage disc, a stationary carrier mechanism for carrying a hollow supply package of yarn and rotatably mounted on the rotor mechanism so that the rotor mechanism rotates relative thereto, a yarn guide eyelet positioned above and in generally axial alignment with the hollow axle, and a driven yarn take-up winding mechanism. With this construction of a spindle assembly, the yarn is withdrawn from the yarn supply package by the winding mechanism and passes through the yarn passageway in the hollow axle and out of the yarn passageway in the storage disc and then upwardly around the outside of the carrier mechanism and the supply package and through the eyelet to the winding mechanism to form a rotating balloon of yarn between the eyelet and the storage disc and around the carrier mechanism and the supply package as a result of the rotation of the rotor mechanism for imparting a two-for-one twist in the yarn. The supply yarn carrier mechanism usually includes a protective pot which is stationary with the carrier mechanism and extends around the outside of the supply package of yarn. There is usually also provided a balloon limitor mechanism which extends around and is spaced from the protective pot device for providing a space therebetween within which the rotating balloon of yarn passes.
The yarn storage disc serves the purpose of talking up a certain reserve of yarn between the location where the yarn emerges from the yarn passageway in the storage disc and the thread balloon to insure a constant yarn tension during processing and a resulting uniform processed yarn. Normally, as shown in Swiss Pat. No. 417,418 and U.S. Pat. Nos. 3,731,478 and 3,834,144, the latter two of which are assigned to the assignee of the present invention, the reserve yarn storage disc includes an outwardly-extending plate attached thereto and of greater diameter than the carrier mechanism including the protective pot thereof and the supply package of yarn, which rotates with the reserve yarn storage disc and the rotor mechanism and which provides a guiding surface within the balloon of yarn so that the balloon can develop into a given physically suitable shape that can rotate freely without coming in contact with the bobbin supply carrier or protective pot, if provided, or with the supply bobbin of yarn to prevent harmful effects caused to the moving yarn by constantly engaging a stationary surface.
However, the windage loss (friction between the rotor and the surrounding air) resulting from rotation of the spindle assembly rotor mechanism is greatly affected by the diameter of such plate, whereby the size of the rotary plate is included to the third or fourth power in the calculation of the windage losses which occur. Also, the greater the windage loss or friction caused by rotation of the rotor mechanism in the surrounding air, the greater the power consumption required for driving of the rotor mechanism.
When overlong, thin supply packages of yarn are utilized, which are often provided by producers of fine denier, continuous filament, synthetic yarn, spindle assemblies have been provided, such as shown in German Pat. No. 875,624, in which the rotating yarn balloon continually rubs against a stationary part of the spindle assembly such as the stationary carrier mechanism due to the overlong narrow configuration thereof dictated by the shape of the supply package. This causes friction between the rotating yarn balloon and the stationary parts of the spindle assembly resulting in fusing of the yarn and breakage therein. Also, yarns of this type are normally treated with softening and other agents that are inclined to deposit sediment and soil on the surface of the stationary parts of the spindle assembly contacted by the rotating balloon of yarn requiring stopping of the machine for cleaning cycles and resulting interruption in the work process which reduces the economical value of the machine operation.
Another known spindle assembly construction for yarn processing machines of this type is shown in German Patent 740,399 wherein the yarn introduced through the hollow spindle axle emerges at the lower end of the spindle radially through an aperture of a sleeve rotating with and at the same rotational speeds as the spindle rotor. To this is added a conically-expanding overrunning member likewise rotating at the rotational speed of the spindle rotor and along which member the yarn is guided. While a spindle assembly design of this type may prevent the harmful consequences of a spindle assembly design according to the aforementioned German Pat. No. 875,624 of constant frictional contact between the rotating balloon of yarn and stationary spindle assembly components, the spindle assembly design of this German Patent 740,339 suffers from the design deficiencies discussed above with respect to Swiss Pat. No. 417,418 by providing a greater windage loss and therefore the need of greater power consumption for driving the rotor mechanism of the spindle assembly.